Evidence for the trapping of a non-Kekulé intermediate in the photoretro-aldol type reaction of m-nitrobenzyl derivatives

Abstract

The acid-catalysed photoretro-aldol type reaction of m-nitro-substituted derivatives was found to give 3-(N-3′-nitrobenzyl-N-hydroxyamino)benzyl alcohol (4) as the only product derived from the nitrobenzyl fragment; the structure of (4) has been determined by X-ray crystallography and the mechanism for its formation requires the intermediacy of a non-Kekulé intermediate in which direct transmission of charge between the 1,3-positions of the benzene ring occurs.